Method of refining mineral oils



' 'lio Patented Sept. 22, 1936 H 2,055,116 METHOD REFINING OIIiS Franz;Rudolf Moser, Amsterdam, Netherlands, assignor to Shell. DevelopmentCompany,v San. Francisco, Calif, a corporation ofDeIawai-e' NdDi-"awingApplication October 8; 1 934 Serial No. 747,419.: In. the Netherlands.October 1'1;

' 8. Claims. (01; rec-36y This invention relates to a processofmanufacturing refinedhydrocarbon oil's andis more particularlyconcerned with atrea'tingjprocess where"- by high grade light fueloils'are obtained. from hydrocarbon mixtures rich in unsaturated; oraromatic components, such for example as cracked, and especially vaporphase crackeddistiliates. I

It is known that the conventional sulfuric acid treatment, when appliedto such dis'tillates,. causes a considerable amount. of'losses,resulting in decreased yields and in" the absence in. the final productsof. various compounds, such as. aromatic and unsaturated hydrocarbons,which are highly desirable. therein, since they tend to. impart to thefuel oil high antiknock properties. i

It is therefore. an object of' this invention to provide a process whichwould" desulfurize, reduce the gum formation and improve the color ofthe distillates treated in a manner comparing favorably with that of thesulfuric acid treatment, while giving at the same time considerablyhigher yields and better octanerating's'.

Briefly stated, this process consists in treating thedesired distillatewith a small quantity of a monoor poly-sulfonic acid" of an aliphaticand/or. aromatic hydrocarbon, either substituted or not, orwith amixture of such acids. The hydrocar'bons to be refined are contacted invapor 30 phase with a solution or suspension of the sulfonic acid in anorganic substance inert at the operating. temperature, which makesitpossible to carry out the process in the presence of steam.

The sulfonic acids which have been found especially suitable for thispurpose are the benzenesulionic acid, the p-naphthalene sulfonic acid,the methane-disulfonic acid, and the sulfonic acids of toluene andxylene. The organic radicles of these acids may be substitutedhydrocarbon groups. It was found that. the substituents exert "adefinite influence. on the process; thus,.sul-

foni'c acids with a negative substituent, such as a halogen (forexample,,parachlorohenzene; sulfonic acid) are usually more suitablethan those with a positive substituent such as the amino groups. Thesesulfonic acids differ somewhat in the action which they exert onthepoil' being. treated. For example, some of them have an especiallyfavorable influence on the color-of the distillate,

while others exert a specific desulf'urizin'g action,

or may increase the anti-knockstability' of the hydrocarbons. Byselecting a. certain sulfonic acid',,or by applying. a mixture of suchacids, the character of the treating actionmay be controlled in anydesired manner. 'Ihe'sulfonic acids must be however,. substantially freeof sulfuric acid, since the latter i's easily reduced at thetemperatures of the process, and the conversion products thus obtainedunfavorably affect the final product.

According to this invention, it is possible to apply the sulfonic acidtreatment to petroleum distillates in the. vapor phase and in thepresence ofsteam; Such method, while very advantageous' forcommercialscale operations, since in the petroleum industry distillationis usually carriedout' with the" aid of steam, wasuntil now:considered'- impracticable, as it" was believed that a continuous supplyof steam would completely hydrolize the sulfonic acids and render themineffective. It has however nowbeen found that substantiallyno suchhydrolysis occurs if the sulfonic acids are dissolved or' suspended, innot too great a concentration, in a liquid organic solvent inert at the;working temperature, which is probably'due to the fact that the organicsolvent'protects the dissolved sulfonic acid from the action of thesteam; The concentration of the acids should preferably be below whilethe allowable upper limit is approximately 10%. Moreover, it isadvantageous towork at a temperature at which there isno substantialhydration, since it has been found that an intensive hydration tends toreduce the solubility of the sulfonic acid in the organic solvent. Thetemperature consequently has to be. fixed for eachacid separately;although temperatures of about 100 to 250 C. have been generally foundvery satisfactory.

The desired inert organic solvent may be selected" from pressuredistillate residues, lubricating'. oils, gas oils, stove oils, Edeleanuextracts, etc. Since it has been found that it is preferable to use theleast. possible amount of the organic solvent capable to protect thesulfonic acid from the hydrolizingfeffect of steam, and since 5111-foni'c acids dissolve more easily in light fractions, it may sometimesbe advisable to dissolve these acids, for example, in a relatively lightEdeleanu extract, and then to admix the solution in desired proportionswith a. heavier oil, such as lu form of a treating column filled withRaschig rings providi'nga large contact surface. known that the lightfractions obtained by cracking", the' so-called pressure distillates,usually require. a" redistillation in order to conform to somedesired-boiling rangespecifications. In practice, such distillation isgenerally carried out with the aidof steam, and the mixture of'steam andhydrocarbon'vapors' thus obtained may, before being. passed. to thecondensing apparatus, be led through the treating column countercurrentto the. treating agent. The treating agentdissolved" or suspended in anorganic inert solvent may be recirculated; and a certain amount offr'esh'sul- It is fonic acid or the solvent continuously added in orderto maintain the desired degree of concentration. It is also possible touse several treating units in series and to pass the hydrocarbon vaporsand the treating agent consecutively and countercurrently. through allof them.

. The'treating column should preferably be constructed of a materialthat does not oxidize easily. Although the metals themselves are notattacked by the sulfonic acids, metal oxides .aredissolved by them sothat corrosion takes place, which is affects unfavorably, the treatingprocess. Stainless steel may be advantageously used forthe constructionof treating columns, whileenamel 1:

.also be combined'withany of the other known methodsfof treating, whichmaybe appliedbephenols, mercaptans, 'etc.

fore as well as after the sulfonic' acidtreatment. For example, the oilmay be pre-treated with dilute acid, lye, or an absorbent material toremove'certain. constituents such as nitrogen bases, In such cases, itis possible to use a concentration of sulfonic acids evenlower thanstated above.

This invention may further be illustrated by jthe followin'g example,without limiting its scope to any of thespecific substances'or stepsused.

A vapor phase cracked. gasoline with the'followin'g properties: octanenumber 69, color'Saybolt, indeterminable, specific gravity 0.753,bromine number 162, gum'300 mg., was distilled with steam, and the vapormixture, containing about 10% steam, and the vapor were passedconsecutively'throughtwo columns filled with Raschig rings, held at atemperature of about 200 C. A

was passed through the secon'd'colum'n counter- 'current, to the vapors,after which the partly spent reagent was mixed with 1% of freshbenfzene-sulfonic acid, and passed through the first column." V a lAfter condensation, agasoline with the follow- 45 ing properties wasobtained: octane number 71, color .Saybolt 2 5, specific gravity 0.752,bromine j number 150, gum 7 mg. The treating losses were very small.

1 j From the above guresitwm be meat that the s50 v tion, is,particularly drawn to they octane numher, which is' even somewhat higherin. the final {product than in. theoriginal gasoline.

process gives, very'satisfactory results. Atten- The relatively smalldecrease of the bromine number shows thatthe unsaturates had notbeenfaffected by the treatment, while the gumrforming components wereeffectively removed from the 'dis- 65.the invention andsubsequentlycondensed, was

, tillatel [It maybe added that ,it'is .sometimes'of advantage toneutralize the acid 'treated distillate with an aqueous solution ofsodiuin carbonate instead of sodium hydroxide. 1 This may have a washedin; one case with sodium carbonate',fand

lin theother case with sodi'inn'hydroxide; .The

gum stability of both gasolineswas determined j t lieilfirst caseandonlyZO in'the second "perature in contact with an effective quantityof hot liquid organic sulfonic acid substantially free from sulfuricacid and separating the treated vapors from the liquid sulfonic acid.not only detrimental to the apparatus, but also"'-- the refining-of apetroleum distillate in the vaporous state the step of subjecting thevapors at a non-cracking temperature to the action of an effectivequantity of hot liquid organicisulfonic acid which is substantially freefrom sulfuric acid.

3. In the refining of a petroleum distillate in thenvaporous state, thestep of subjecting the vaporsat a temperaturebetween 100 C. and

tillate in the vaporous state the step of subjecting the vapors at anon-cracking temperature to the ,act ion of a hot liquid solution oforganic sulfonicacid in an organic solvent which is substantiallyinactive underthe conditions of the treatment, said solution beingsubstantially free from sulfuric acid;

5; In the process of'treating a petroleum distillate in the vaporousstate the step of subjecting the vapors at a non-cracking temperature tothe actionof a hot liquid solution of organic sulfonic acid,.sa'idsolution containingnot more than 10% sulfonic acid in an organic solventwhich is substantially inactiveunder the conditions of the treatment andis substantially free from sulfuric acid. 6. In the refining ofa'petroleum distillate in the vaporousfstate' the step of subjecting thevapors at a" non-cracking temperature in the presence of steam to the,action of an effective quantityof hot liquid organic sulfonic acid,which is substantially free from sulfuric acid, and under conditions toprevent the condensation of steam.

"7. In the refining'of apetroleum distillate in the vaporous statethestep of subjecting the vapors at anon-cracking temperature of saiddistillate to'the action of an efiective' quantity of hot liquid organicsulfonic acid, which is substantiallyfree from sulfuric acid, and under,

conditions to prevent the formation of metal sulfonates.' v

8. In the process of treating a hydrocarbon I Idistillateof the type ofgasoline in the vaporous state to produce astable gasoline of good colorand low gum content the steps of subjecting the vapors ata temperaturebetween" C. and

",tainingnot'more than'l0% of sulfonic acid in an organic solvent whichis substantially inactive under the conditions of the treatment, andunder conditions to prevent formation of metal sulfohatesseparatirig'the vapors from the treating;v I solution, condensing the treated Ivapors, and treating'jthe resulting condensate with an aqueous solutionof sodium carbonate, 'whereby a gasoline is produced possessinganoctane, number which is higherv than that :of the original distillate. V

